RARE TEAC Dual SCSI Floppy Drive
model FD-235HS 711 -U
(which includes two different style FD-235HF floppy drives
mounted together with one TEAC FC-1 SCSI floppy controller)



This page has 21 Synhouse reference photos of the very rare TEAC dual SCSI floppy drive rack setup
with the integral bottom-mounted TEAC FC-1 SCSI floppy controller.

It is shown both assembled and in parts.

Note: This was not used with a PC, Mac, or other consumer desktop computer, it was used in a laboratory in an embedded system. The units Synhouse presently has in stock are spare parts that came from the liquidation of a servicing distributor of laboratory machines. Most or all of these parts were made in late 1994.


This is the entire assembly of two (slightly different) TEAC 3.5" high density floppy drives between two heavy steel mounting brackets, with the TEAC FC-1 SCSI controller on the bottom, shown from all four sides, plus the bottom:






(Please note that the two black metal mounts are included,
and you can flip them over to bolt the drives to a surface above if you prefer.)







This in the photo below is the holy grail of floppy drive products, the TEAC FC-1 SCSI floppy controller, TRY2FIND1:



Note that this assembly was obviously put together and stocked in the US.
It has drives made in Thailand (similar to the common PC units, but with rare black/tall faceplates to enclose the FC-1 SCSI board),
the FC-1 SCSI controller made in Japan, US-made sheet metal, and an Ansley flat cable assembly made in the US of US-made cable and connectors.




Here are some rear views of the assembly, with the flat cable removed for visibility, so you can see the SCSI termination resistor packs and jumpers:




Note that the TEAC numbers don't really make any sense to me.

These appear to be functionally identical drives, and they work as functionally identical drives, with the only important visible difference being the vertical dual row header on the lower drive and the right angle dual row header on the upper drive. This was done so that a very tiny flat cable could connect all three units in a tiny space.

Additionally, the PCBs are slightly different, and one has the spinning flywheel exposed on the bottom, where the other has it covered.

The tags say FD-235HF.

The TEAC website isn't particularly helpful, saying that all 3.5" TEAC drives have that number, and that the extension suffix makes the difference, but I have a number of these, and yes, the top drive is always numbered different from the bottom drive, but one top drive has a different suffix number than another top drive, when they are obviously functionally identical, otherwise they couldn't serve as replacement parts for the same system. The same differences apply for the bottom drives.

The ones shown on this page are:

Top: FD-235HF 6529 -U5

Bottom: FD-235HF 3700-U


Another identical set I have are:

Top: FD-235HF 4240 -U5

Bottom: FD-235HF 3700-U


So, the FD-235HF 6529 -U5 and FD-235HF 4240 -U5 are being used interchangeably, and there are even more different numbers yet.

So, my point is, don't read too much into the numbers.

The TEAC site about it makes no sense, it is here and here, among other places.

It is either not all-inclusive, not updated, or the ones I have were special part numbers for an OEM.



These floppy drives, aside from being black in color, have a much more hectic jumper block than the usual PC drives (which often have only three pins or none):





(The exact unit shown for these representative photos has SCSI pin 1 removed or broken off. SCSI pin 1 is one of 20 or 30 ground pins in the narrow SCSI interface, and pin 1 is not required. Apple sold hundreds of thousands of computers and other machines with only 25 pins for SCSI.)




I tested these out the only way I knew how, by separating the drives into different items, setting them to floppy AB instead of BC, and connecting them to a standard PC floppy controller bus, and formatting a disk to 1.44mb. They worked perfectly.

The photo below shows an upper drive under test:







Note that the lower drive is of standard dimensions,
but the top drive has a special custom FC-1 black bezel that extends down (and up) and covers the FC-1 and frame:











Once again, the holy grail of floppy drive products, the TEAC FC-1 SCSI floppy controller:





This is the special protective mounting plate for the TEAC FC-1:






The photo above shows the 13 pieces of hardware that are included to finish the assembly. Four are special 2mm Allen screws that hold the FC-1 frame to the lower drive, and the rest are just standard screws to hold the drives into the side panels and to hold the lower bezel onto the FC-1 frame.


The next four photos show a comparison of the two different drive styles here: